Recording Transient Solution Data

Before running a transient simulation, define the solution data you wish to save using a solution history. Simcenter STAR-CCM+ writes one simulation history file (.simh) per solution history node. You can create multiple solution history nodes in the same simulation.

The simulation history files that you create are located under the Solution Histories manager node. You can select what data is stored in these files and how often the data is saved to file.

If your simulation contains any motion objects, the resulting motion data is automatically saved to the simulation history file. For each motion, this data includes the origin, axis, rotation rate, rotation angle, velocity, transformation matrix, accumulated transformation matrix, and some necessary boolean attributes.

Coordinate system data of the simulation is also automatically saved. This includes the origin and base coordinate system data.

Each simulation history file node contains two sub-nodes: the Update node, that controls how the update frequency is defined, and the Update Frequency node, where you can specify how often the updates take place.

To set up a simulation history file:

If you have not yet done so, save the simulation file you are working with. This step ensures that solution history files are created with a location relative to the simulation file.
To create the solution history file:
1. Right-click on the Solution Histories node and select New...
2. In the Save dialog, choose a location that has adequate space and give the file an appropriate name.
3. Click Save.
A new sub-node with the name of the simulation history file appears in the Solution Histories node. Simultaneously, a solution view node with the same name is added within the Solution Views node. In the following example, the simulation history file was given the name pressureAndVelocityData.

The red asterisk next to this node indicates that Simcenter STAR-CCM+ is set to write data to the simulation history file when you run the simulation. The property, Auto-record, controls whether the simulation actively writes to this file or not. Another property, Auto-Rescan, instructs the simulation to synchronize the data stored in the corresponding solution view representation after each export event.

Simcenter STAR-CCM+ allows you to choose regions or standalone objects from which to record data. Standalone objects include boundaries, part surfaces, derived parts, Lagrangian phases (for particle data), and DEM phase interactions. You are advised to choose standalone objects in preference to regions, as this practice keeps the size of the simulation history file to a minimum. If a boundary has a great number of part surfaces, you can choose to export individual part surfaces rather than the entire boundary. If you choose regions, Simcenter STAR-CCM+ writes the selected field function data for every cell in the region. In addition to a larger .simh file, this export can cost more computing power.

All coordinate systems and motion data (except for motion driven by 6-DOF Bodies, that is, DFBI) in the simulation, are included in the export automatically. You do not need to select anything for these types of data.

Before recording solution data in a simulation history file, you are advised to add any derived part from which you want to extract data to the solution history inputs—so that the data is stored during the simulation. This approach is preferable to creating a derived part later in the recorded solution view. In general, the interpolation accuracy that is achieved during the solution run cannot be obtained from recorded history files.

Note	The following derived parts can consist of volume data rather than surface data, and so cannot be recorded to a simulation history file: cell surface, resampled volume, threshold, and vortex core.

Choose objects on which to save data:
1. Select the [solution history] node and set Inputs to standalone objects (including derived parts) from which to record data.
2. If you do require region data, set Regions to regions from which to record data.
To choose the scalar or vector data that Simcenter STAR-CCM+ writes:
1. Click the (property customizer) button located next to Functions.
2. In the object selection dialog, select the desired scalars or vectors, then click OK.
3. Consider whether to activate the properties Export for reporting and Export inputs at non-native locations.
  See Solution History Properties.

Decide whether to compress the simulation history file using the Compression mode property. The default mode is Lossless.

See Solution History Properties.

Note	In the current release, only surface and volume data, that is, mesh information and field data, is saved in compressed format when you activate compression. Moreover, to preserve network connectivity, compression is not applied to coordinate values (such as for mesh vertices).

Set the frequency with which Simcenter STAR-CCM+ writes data to the file. You can set time-intervals or iteration counts, or else define update events that depend on multiple factors:
1. Select the [solution history] > Update node and set Trigger to one of the options.
2. Select the child node and set its properties.
  - For Iteration, Time Step, or Delta Time, you typically set the Start, Stop, and Frequency of the chosen factor.
  - For an update event, you must first create the update event within Automation > Update Events, and then choose this event within the Update > Event Frequency node for the solution history.
After setting up all the simulation histories, proceed with running the simulation.